You can use the Boinc manager on your Raspberry Pi however the World Community Grid project is not supported on Raspberry Pi. However there's other projects you could run on your Pi, see the list here: https://boinc.berkeley.edu/projects.php and look for the ones that say they supported on ARM processors.
You might need to adjust the computing preferences a bit for your Pi, I noticed that if you set it to run always or very close to 100%, it'll hit 85 degrees Celsius pretty quickly and at that point the CPU starts to throttle. At least that is what I noticed on mine.